Molecular structure and thermodynamic parameters of (5656)macrotetracyclic chelates in the 3d-element(ii) ion-hydrazinomethanethiohydrazide-2,3-butanedione ternary system according to density functional quantum-chemical calculations

Abstract

The thermodynamic and geometric parameters of the macrocyclic chelates of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with the (NNNN) coordination of the ligand donor centers formed upon complexation between the above metal ions, hydrazinomethanethiohydrazide (H2N-HN-C(=S)-NH-NH2), and 2,3-butanedione (H3C-C(=O)-C(=O)-CH3) in gelatin-immobilized matrix implants were calculated by the B3LYP 6–31G(d) density functional theory method with the use of the Gaussian 09 program package. The bond lengths, valence angles, and torsion angles were reported, and it was noted that the complexes of Fe(II), Co(II), Ni(II), and Cu(II) are almost planar, whereas the complexes of Mn(II) and Zn(II) have a quasi-pyramidal structure of the chelate unit. The additional six-membered metallocycles resulting from template cross-linking, as well as five-membered rings, are almost planar.